Wow wow wow. That was more than I was expecting. The police got criticised for weeks but of course they were very very busy linking all this. This is excellent police and forensic work.
The knife sheath was one of many “clumsy” mistakes he made for sure. Given it was found with the two girls I guess he took it off the knife there, the first victims. Then, did he hear the delivery driver arrive and “panic” and so it wasn’t at the forefront of his mind. It got left. He went to silence X as she was near the exit point for him, and found she had E there. He stabbed them and was spooked and high on adrenaline and left. Did he only go in there for one girl and ended up doing four victims? I don’t think he knew that Dylan had seen him. That would explain for weeks and weeks the narrative was that Dylan and Bethany were asleep. They had to say that so that they were safe.